<!DOCTYPE html>
<html lang="zh_CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<script type="text/javascript">
    var a = 1;
    var b = a; // 值的拷贝 b = 1;
    console.log('最先b的值', b);
    b = 10;
    console.log('b的值', b); // 10
    console.log('a的值', a); // 1
</script>

</html>
